Because of its variable transmission, self-priming ability is strong, reversible, can transport liquid containing solid particles and other characteristics, in sewage treatment plants, is widely used in the transport of water, wet sludge and flocculant liquid. Screw pump selection should follow the principle of economy, reasonable, reliable. If the design and selection are not well considered, it will bring trouble to the use, management and maintenance of the future, so the selection of a progressing cavity pump according to the actual production needs, reasonable and reliable can not only ensure the smooth production, but also reduce repair costs.
First, screw pump speed selection
A linear relationship with screw pump flow rate and rotational speed, low relative to the rotating speed of screw pump, high rotational speed of screw pump, can increase the flow and head but power obviously increase, high speed accelerate the abrasion between the rotor and stator, must make the premature failure of screw pump, and the high speed of the screw pump stator length is short, easy to wear and tear, thus shortening the service life of the screw pump.
Through the deceleration mechanism or stepless speed regulation mechanism to reduce the speed, so that the speed is maintained in a more reasonable range of three hundred revolutions per minute, compared with the high-speed operation of the screw pump, the service life can be extended several times.
Two, the quality of screw pump
Now there are more types of screw pump on the market. Relatively speaking, the imported screw pump has a reasonable design and excellent material, but the price is higher, some services are not in place, the price of accessories is high, the order cycle is long, which may affect the normal operation of production. Most of domestic production imitation imported products, product quality good and bad are intermixed, when choosing the product of domestic production, when considering its cost performance ratio, choose low speed, long lead, transmission quantity parts material quality is good, rated life long product.
Three, ensure that the debris does not enter the pump body
Wet sludge mixed with solid impurities can cause damage to the rubber material of screw pump stator, so make sure debris into the cavity of the pump is not very important, a lot of sewage plant in front of the pump with a grinder, also some installation or mesh grille device, stop the debris into screw pump, the grating should be timely get so as not to cause congestion.
Four, avoid broken material
Screw pump must not be allowed in the case of the cutting operation, once happened, screw pump outlet pressure of the rubber stator due to dry friction, instant high temperature and burn out, so, crushing machine in good condition, grille flow is one of the necessary conditions for normal operation of the screw pump, therefore, some screw pump on pump installation end stop device, when cutting, due to the characteristics of the screw pump has a self-priming function, can produce vacuum chamber, vacuum device can make the screw pump stop running.
Five, maintain a constant outlet pressure
Progressive cavity pump is a positive displacement rotary pump, when the outlet end is blocked, the pressure will gradually rise, so that it exceeds the predetermined pressure value. The motor load increases sharply at this time. The load of related parts of transmission machinery will also exceed the design value. In serious cases, the motor will burn down and the transmission parts will break. In order to avoid screw pump damage, generally installed in the screw pump outlet bypass relief valve, in order to stabilize the export pressure, maintain the normal operation of the pump.
